Technical Field
This disclosure is related to composite transparent conductors based on conductive nanostructures, and methods of forming the same.
Description of the Related Art
Transparent conductors refer to optically transparent, thin conductive films. They are widely used as transparent electrodes in flat panel electrochomic displays such as liquid crystal displays, plasma displays, touch panels, electroluminescent devices and thin film photovoltaic cells, as anti-static layers and as electromagnetic wave shielding layers.
Conventional transparent conductors include vacuum deposited metal oxides, such as indium tin oxide (ITO). However, metal oxide films are costly to fabricate because they require vacuum chambers, elevated deposition temperatures and/or high annealing temperatures to achieve high conductivity. Metal oxide films are also fragile and prone to damage even when subjected to minor physical stresses such as bending.
Conductive polymers have also been used as optically transparent electrical conductors. However, they generally have lower conductivity values and higher optical absorption (particularly at visible wavelengths) compared to the metal oxide films, and suffer from lack of chemical and long-term stability.
Conductive nanostructures can form optically transparent conductive films due to their submicron dimensions. Copending and co-owned U.S. patent application Ser. Nos. 11/504,822, 11/871,767, and 11/871,721 describe transparent conductors formed by networking anisotropic conductive nanostructures such as metal nanowires. Like the ITO films, nanostructure-based transparent conductors are particularly useful as electrodes that can be coupled to thin film transistors in electrochromic displays such as flat panel displays and touch screens. In addition, nanostructure-based transparent conductors are also suitable as coatings on color filters and polarizers, as polarizers, and so forth. The above copending applications are incorporated herein by reference in their entireties.
There is a need to provide cost-effective and high-performance nanostructure-based transparent conductors to satisfy the rising demand for quality display systems.